A PAT test is an electrical safety test for any item with a plug attached. Portable appliance testing of electrical items used for a professional purpose is compulsory with electrical safety acts. When an item has passed a portable appliance test a green pass sticker is placed on the appliance, the date when the item should be re-tested is written on the sticker. PAT tests should be carried out annually.
The same way a car needs to go through an MOT once a year, an electrical item requires a P.A.T once a year.
Most venues actually require each piece of DJ gear to be PAT tested before they are even allowed into the venue. Every single electrical item we own has been PAT tested, proof is on the item (The green sticker), we can also e-mail a list of gear which has been tested signed by our PAT tester with his contact details if needed.